One of the WTC architects (Aaron Swirski) was interviewed Sept 11th, by"Jerusalem Post Radio." Among other things, he said that what was beingreported was incorrect. He said it was being reported that 50,000 peopleworked at the WTC when in fact it was 500,000.

This was said shortly after the 2 minute, 40 second point in a 4 minuteinterview. The interviewer kept on this point, repeated what he said and hadhim repeat it. There is no doubt that in his understanding there were half amillion people who worked in the WTC complex, presumably the two main towerscontaining the bulk of the employees.

JERUSALEM (September 12) - Aaron Swirsky, one of the architects of the World Trade Center, yesterday expressed disbelief on hearing of the collapse of the twin towers. Swirsky told JPostRadio the buildings had been designed with "accidents" in mind.

"The terrorism was different in those days, but there was always the possibility of an accident with a plane hitting the building. The building was designed like a pipe structurally, with the main structure in the perimeter of the building." This meant that a hole in the building would not collapse the whole structure. The fact that the buildings did collapse he described as "incredible."

Swirsky said the 1993 bombing of the World Trade Center made a big hole in one building. "The intent was to topple the building, but because of the design it didn't. But now... it is unbelievable." He said the collapse may have been due to the size of the plane, bigger than the architects had ever planned for.

The floors above the crash sites would have been safe, at least at first, said Twirsky. "What is really tragic is the building was designed with each floor as a hermetic unit, as to evacuate a building like that is a nightmare. Imagine you are on the 100th floor and there is no elevator, so each floor is designed to be safe; but when it collapses then that whole theory goes up in smoke."

The buildings had no sprinklers, because each floor could be sealed off from the others in case of a fire. "There are shutters that would shut off the vertical openings [between floors] so that the fire couldn't travel from one floor to the other. That was the theory. When the danger had subsided they could evacuate."

After the planes crashed into the buildings, Swirsky said people in the floors above would have been trapped. They would have been unable to escape. The buildings were not designed to allow for a quick exit in case of emergency. Afterward, those trapped would have fallen with the buildings when they collapsed.

(CNN) -- When they were completed in the early 1970s, the Twin Towers of New York's World Trade Center were the tallest buildings in the world. That designation didn't last long -- Chicago's Sears Tower took the title in 1974, a year after Two World Trade Center was finished -- but the buildings' standing as a New York City landmark, anchors amid the office-tower canyons of Manhattan's financial district, remained unchallenged.

Tuesday, the buildings -- daytime home of more than 50,000 workers -- were destroyed when two hijacked passenger jets were flown into the structures.

CNN's Leon Harris spoke with Aaron Swirsky, part of the architectural team led by World Trade Center chief architect Minoru Yamasaki, on the way the building was designed.

LEON HARRIS, CNN ANCHOR: So many of us had thought for so long that the Twin Towers were invincible. We had heard for so many times over the years that the buildings have been built to withstand an impact from the crash of a plane.

Let's talk right now on the telephone with Aaron Swirsky. He's in Jerusalem. He was one of the original architects of the complex, as I understand it.

Is that the case, Mr. Swirsky?

AARON SWIRSKY, ARCHITECT: I was working with Minoru Yamasaki, who is the architect of the building. But I was one of the workers with him. We were a team of 14 architects, and I was one of the members of the team.

HARRIS: As a member of the team, and having such insight to how this building was constructed, could you believe that a plane could bring these buildings down?

SWIRSKY: No, as a matter of fact, one of the rationales of the structure of the building was that it would be built as a pipe. And that proved itself to work during the explosion of 1993, when a hole was brought into the building, and it survived. But somehow, nobody could foresee anything like (Tuesday's incident).

Also, at that time, the planes were not like these types of planes that we have now. I think the biggest plane was a 100-passenger plane, something like that, and the fuel capacity of those planes was not like they are today.

The criterion was that if a plane hits, it would go right through it. And nobody could foresee something like that. The tower was protected in such a way that the damage would be limited to one story, but it wouldn't travel to the other stories.

HARRIS: The planes that crashed yesterday were much bigger than that. They were 757s.

SWIRSKY: And also the fuel capacity is much more tremendous.

HARRIS: Exactly. That's what I want to ask you about. Which was it that made the biggest difference? Was it the impact felt from the larger plane, or was it the heat generated by the burning and that much fuel.

SWIRSKY: I imagine, when I saw the pictures of the implosion of the building, it looks like the fuel must have leaked right to the core of the building, and from there it was the massive explosion that caused the building to collapse. So it was something completely unforeseen, so far as the design criteria was (concerned).

HARRIS: Let me ask one final question, if I may. Considering what you know about the building -- you say it was constructed like a pipe, these two buildings -- and the manner in which we saw them collapse, does that give you any hope at all that the way it collapsed, there will be more packets inside, at the bottom, where survivors could be found?

SWIRSKY: Well, I sure hope so. We pray that there will be survivors and that this won't happen again. It's a terrible, terrible, incredible tragedy.